GRB230518A

This page lists all entries on GRB230518A in GRBweb

Summary Fermi GBM GCN 33822 GCN 33825 GCN 33828 GCN 33843

Summary table
Variable Value Source
GRB_name_Fermi GRB230518951
T0 22:49:26.841 UTC Fermi_GBM
ra 19.5210° GCN_circulars,IPN Triangulation
decl -66.5940° GCN_circulars,IPN Triangulation
T90 0.896 s Fermi_GBM
T90_error 0.286 s Fermi_GBM
T90_start 22:49:26.841 UTC Fermi_GBM
fluence 9.45e-08 erg/cm² Fermi_GBM
fluence_error 7.06e-09 erg/cm² Fermi_GBM
T100 0.896 s
GBM_located False
mjd 60082.951005104165 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB230518951
trigger_name bn230518951
ra 256.3500°
decl -49.6200°
pos_error 1.04e+01°
datum 2023-05-18
t_trigger 22:49:27.609 UTC
T90 0.896 s
T90_error 0.286 s
T90_start 22:49:26.841 UTC
fluence 9.45e-08 erg/cm²
fluence_error 7.06e-09 erg/cm²
flux_1024 1.29e+00 erg/cm²/s
flux_1024_error 2.05e-01 erg/cm²/s
flux_1024_time -7.68e-01 erg/cm²/s
flux_64 3.67e+00 erg/cm²/s
flux_64_error 1.00e+00 erg/cm²/s
GCN 33822 table
GRB_name GRB230518A
GCN_number 33822
Detection_method Fermi GBM final loc
t_trigger 22:49:27 UTC
ra 256.4000°
decl -49.6000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 33822 SUBJECT: GRB 230518A: Fermi GBM Final Real-time Localization DATE: 23/05/18 22:59:56 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely SHORT GRB At 22:49:27 UT on 18 May 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230518A (trigger 706142972.60896 / 230518951). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 256.4, Dec = -49.6 (J2000 degrees, equivalent to J2000 17h 05m, -49d 36'), with a statistical uncertainty of 19.0 degrees. The angle from the Fermi LAT boresight is 23.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230518951/quicklook/glg_skymap_all_bn230518951.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230518951/quicklook/glg_healpix_all_bn230518951.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230518951/quicklook/glg_lc_medres34_bn230518951.gif
GCN 33825 table
GRB_name GRB230518A
GCN_number 33825
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 33825 SUBJECT: GRB 230518A: Swift/BAT-GUANO detection DATE: 23/05/19 11:34:53 GMT FROM: Aaron Tohuvavohu at University of Toronto Samuele Ronchini (PSU), Gayathri Raman (PSU), James DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT did not localize GRB 230518A onboard (T0: 2023-05-18T22:49:27.61 UTC, Fermi/GBM GCN 33822). The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), detects the burst with a sqrt(TS) of 11 in a 0.128 s analysis time bin. The burst duration is ~0.256 seconds. NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a borderline DeltaLLHOut of 6.5. The majority of the Fermi/GBM localization lies outside the coded FOV. See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
GCN 33828 table
GRB_name GRB230518A
GCN_number 33828
Detection_method Fermi GBM Det
t_trigger 22:49:27.610 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 33828 SUBJECT: GRB 230518A: Fermi GBM Observation DATE: 23/05/19 17:07:45 GMT FROM: sumanbala2210@gmail.com S. Bala (USRA), C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 22:49:27.61 UT on 18 May 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230518A (trigger 706142972/230518951). which was also detected by Swift/BAT-GUANO (S. Ronchini et al. 2023, GCN 33825). The Fermi GBM Final Real-time Localization was reported in GCN 33822. The angle from the Fermi LAT boresight is 23 degrees. The GBM light curve consists of one short peak with a duration (T90) of about 0.9 s (50-300 keV). The time-averaged spectrum from T0-0.7 to T0+0.2 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is 0.6 +/- 0.7 and the cutoff energy, parameterized as Epeak, is 503 +/- 138 keV. The event fluence (10-1000 keV) in this time interval is (5.5 +/- 0.9)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0+0.0 s in the 10-1000 keV band is 4 +/- 1 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN 33843 table
GRB_name GRB230518A
GCN_number 33843
Detection_method IPN Triangulation
t_trigger 22:49:28 UTC
ra 19.5210°
decl -66.5940°
Circular_text TITLE: GCN CIRCULAR NUMBER: 33843 SUBJECT: IPN triangulation of GRB 230518A (short) DATE: 23/05/21 13:50:51 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko, on behalf of the IPN, A. Goldstein, M. S. Briggs, C. Wilson-Hodge, and E. Burns on behalf of the Fermi GBM team, E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, report: The short-duration GRB 230518A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 33822; Swift-BAT/GUANO detection: Ronchini, GCN Circ. 33825) has been detected by Fermi (GBM trigger 706142972), Swift (BAT), and INTEGRAL (SPI-ACS), so far, at about 82168 s UT (22:49:28). The burst was outside the coded field of view of the BAT. We have triangulated it to a GBM-SPI-ACS annulus centered at RA(2000)=19.521 deg (01h 18m 05s) Dec(2000)=-66.594 deg (-66d 35' 40") whose radius is 88.662 +/- 2.786 deg (3 sigma). The annulus combined with the Fermi-GBM final position (GCN 33822; glg_healpix_all_bn230518951_v00) gives 480 sq. deg (3 sigma) localization region. The localization is inconsistent with the localization of the NSBH merger event candidate S230518h (LVK Collaborations, GCN Circ. 33813, 33816). A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB230518_T82167/IPN/